Answer: true
Step-by-step explanation:
Z-tests are statistical calculations that can be used to compare the population mean to a sample mean The z-score is used to tellsbhow far in standard deviations a data point is from the mean of the data set. z-test compares a sample to a defined population and is typically used for dealing with problems relating to large samples (n > 30). Z-tests can also be used to test a hypothesis. Z-test is most useful when the standard deviation is known.
Like z-tests, t-tests are used to test a hypothesis, but a t-test asks whether a difference between the means of two groups is not likely to have occurred because of random chance. Usually, t-tests are used when dealing with problems with a small sample size (n < 30).
Both tests (z-tests and t-tests) are used in data with normal distribution (a sample data or population data that is evenly distributed around the mean).
Answer:
(7,2)
Step-by-step explanation:
x + y = 9 + 2x - 3y = 8 is really two equations, and you should show this by separating x + y = 9 from 2x - 3y = 8 through the use of a comma, or the word "and," or through writing only one equation per line.
Here you have the system of linear equations
x + y = 9
2x - 3y = 8.
Let's solve this system by elimination. Mult. the 1st eqn by 3, obtaining the system
3x + 3y = 27
2x - 3y = 8
-------------------
5x = 35, so that x = 7. Subbing 7 for x in x + y = 9, we get 7 + y = 9, indicating that y = 2.
Thus, the solution to this system of equations is (7,2).
Answer:
0
Step-by-step explanation:
